This Tesla coil was designed to run on a 900 Watt neon transformer. Unfortunately, all I had was a 240 Watt neon transformer, which was still enough to generate 175,000 Volts with streamers up to 18" long. It cost about $50 to build (not including the neon transformer).

Fundamentals of the Tesla Coil

A Tesla coil is a high voltage transformer with an air core. The primary and secondary coils each have inductance and capacitance so they function as an LC circuit with its own resonant frequency. The primary capacitance comes from a capacitor that discharges across the spark gap when the voltage is high enough. The secondary capacitance comes from the coil itself and the sphere or toroid at the top. When both circuits have the same resonance frequency, the oscillations efficiently contribute to the induced voltage.

Tesla Coils

This was my first Tesla coil built in 1994. It didn’t work very well. The picture on the right shows a rotary spark gap that was used.

Here is my second Tesla coil built some time around 1994. The secondary coil is 3.5" diameter × 14" tall and has 996 turns. The original design was closely modelled after Gordon McComb’s book, Gadgeteer’s Goldmine. It never worked very well, but I think it will work quite nicely now that it has been modified. The left picture shows the original coil and the right picture shows the new modified design.

This was my third Tesla coil built in 1995. This is the same coil as shown at the top of this page. The design was based on John Couture’sTesla Coil Design Manual (1992). The secondary coil is 5" diameter × 20" tall and has 508 turns. It is interwoven with fishing line and coated with enamel to improve the insulation between turns.

This miniature Tesla coil was also built some time around 1995. The secondary coil is 1.625" diameter × 6.375" tall and has 1080 turns.

Van De Graaf Generator

That is what I call a bad hair day! The static electricity is causing her hair to repel. The pictures on the right show my first Van De Graaf generator built in 1994.